Vascular access for renal dialysis is a lifeline for about 120,000 patients in the United States. Detection of access compromise is critical for optimal management. The proposed seeks to develop a new method for early and accurate detection of decreased access patency. The essential hypothesis is that vascular compromise alters blood flow turbulence resulting in diagnostic vibration ("acoustic") changes detectable at the skin surface. The proposed technology is based on computerized analysis of signals from "electronic stethoscopes" placed on the patient?s forearm. This is not an imaging technology. Rather, it is a much less expensive, yet potentially powerful method for immediate and safe diagnosis. Phase 1 research will test feasibility by studying fifteen human subjects before and after vascular access angioplasty. If successful, the novel device would have significant commercial potential with purchase by renal dialysis units and radiology departments. A much larger potential market may exist as the knowledge garnered in this effort is later applied to other vascular applications such as stroke prevention, renal artery stenosis detection, femoral-popliteal bypass graft salvage, and to early diagnosis of abdominal aortic aneurysms. PROPOSED COMMERCIAL APPLICATION: If this technology proves successful, it is anticipated that the device would become standard equipment in renal hemodialysis units world-wide with potential estimated sales in the order $30,000,000. Annual sales of disposable sensors are estimated to total an additional $25 million. A much larger potential market may exist as the knowledge garnered in this effort is later applied to other vascular applications such as stroke prevention, renal knowledge garnered in this effort is later applied to other vascular applications such as stroke prevention, renal artery stenosis detection, femoral-popliteal bypass graft salvage, and to early diagnosis of abdominal aortic aneurysms.